Over the last four decades, the density of integrated circuits has increased by a relation known as Moore's law. Stated simply, Moore's law says that the number of transistors on integrated circuits (ICs) doubles approximately every 18 months. Thus, as long as the semiconductor industry can continue to uphold this simple “law,” ICs double in speed and power approximately every 18 months. In large part, this remarkable increase in the speed and power of ICs has ushered in the dawn of today's information age.
Unlike laws of nature, which hold true regardless of mankind's activities, Moore's law only holds true only so long as innovators can continue to overcome the technological challenges associated with it. In particular, one trend to increase transistor density in recent years is to go to nonplanar semiconducting devices—so called “FinFETs.” FinFETs include a silicon fin, which includes source and drain regions that are separated by a channel region in the fin. A gate “wraps” around an upper surface and sidewalls of the channel region in the fin. This 3-dimensional channel structure increases the effective gate width of the FinFET over a planar FET, which allows for increased gate control of the channel region.